Osama bin Laden spent his final years struggling to exert authority over the al-Qaeda network he founded, voicing dismay about the decisions of regional affiliates and drafting orders for often unresponsive subordinates even just one week before he was killed, according to documents released Thursday.

The letters, part of a trove of material recovered during the U.S. raid on bin Laden’s compound last year, include chilling admonitions to remain focused on killing Americans. They also cast doubt on suspicions that the governments of Pakistan and Iran collaborated with the terrorist group and reveal bin Laden’s concerns about a U.S.-born cleric who was rising through the ranks of al-Qaeda’s franchise in Yemen.

The documents, declassified by the Obama administration, represent only a small fraction of the material recovered in the bin Laden raid, a sample that seems aimed at exposing the discord between al-Qaeda’s core and the franchises that are now considered more worrisome national security threats.

But the files also provide an intriguing glimpse into the aging al-Qaeda leader’s thoughts as his life neared its end. He expressed concern that the group’s brand had been tarnished by attacks against Muslims, and that the group had become distracted by regional fights.

“Our strength is limited,” bin Laden wrote in a 2010 letter that compared the United States to a tree with branches that project across the world. “So our best way to cut the tree is to concentrate on sawing the trunk.”

The details are embedded in a collection of 17 files that span 175 pages and were made available online by the Combating Terrorism Center at the U.S. Military Academy at West Point. The organization had exclusive access to the material for several months and issued a report summarizing its findings.

The release came one year and one day after bin Laden was killed, and coincides with new efforts by President Obama to make the administration’s counterterrorism achievements a central part of his reelection campaign. The files cover a span from 2006 to the week before bin Laden’s death.

In a 2010 letter to one of his top deputies, bin Laden expressed alarm about the “increased mistakes” committed by the “brothers” in countries including Iraq and Yemen, and he pushed to bring the groups in line.

Bin Laden harbored doubts about Anwar al-Awlaki, the American-born propagandist who was a rising figure in al-Qaeda in the Arabian Peninsula, or AQAP, as the Yemen affiliate is known.

Awlaki should “remain in his position” and not be placed in charge of AQAP, bin Laden said. He instructed the affiliate to submit a detailed résuméon Awlaki and let him prove himself in battle. “We here become reassured of the people when they go to the line and get examined there,” bin Laden said. Awlaki was killed in a CIA drone strike in Yemen in September.

The documents also provide at least partial answers to questions about al-Qaeda’s relationship to the governments of Pakistan and Iran.

The West Point report notes that “there are no explicit references to any institutional Pakistani support for al-Qaeda and its operatives,” despite lingering suspicion that the country’s intelligence service helped shelter bin Laden in Abbottabad, Pakistan.

The Combating Terrorism Center acknowledged, however, that it had no access to thousands of bin Laden records that have not been declassified. A White House spokesman said Thursday that no additional releases are planned.

The letters depict a suspicious, antagonistic relationship between al-Qaeda and Iran, which detained operatives and their relatives who fled after the U.S. invasion of Afghanistan. Al-Qaeda secured the release of some of those held, including members of bin Laden’s family, by kidnapping an official at the Iranian Consulate in Peshawar, Pakistan, the documents indicate.

Fearing that Iran or the United States would seek to follow those relatives to his hide-out, bin Laden instructed them to switch cars in the tunnel between Kuhat and Peshawar. They should also get “rid of everything they received from Iran, like baggage or anything, even as small as a needle as there are eavesdropping chips that are developed to be so small,” bin Laden wrote.

The analysts at West Point concluded that al-Qaeda’s ties to Iran were the “unpleasant byproduct of necessity, fueled by mutual distrust and antagonism.’’

U.S. officials have described the complete collection of bin Laden material as the largest cache of terrorism files ever obtained, with about 100 flash drives and DVDs as well as five computer hard drives, piles of paper and a handwritten journal kept by the al-Qaeda chief.

Many details contained in the newly released files have been previously reported, including bin Laden’s desire to target Obama so that an “unprepared” Vice President Biden would be thrust into the Oval Office.

The files reveal a widening gap between bin Laden and his longtime deputy, Ayman al-Zawahiri. Instead, bin Laden appears to have become increasingly close to another subordinate, Atiyah abd-al Rahman, who was the frequent recipient of missives that make the al-Qaeda leader seem out of touch with how depleted his organization had become.

“It would be nice,” bin Laden wrote repeatedly in a 48-page letter to Rahman that contains daunting requests. Among them are to move followers out of the reach of CIA drones, fix the network’s followers and train new recruits on aircraft. It also instructs Rahman to locate a “brother distinguished by his good manners, integrity, courage, and secretiveness, who can operate in the US.”